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| author | Will Deacon <will.deacon@arm.com> | 2010-12-02 17:01:49 (GMT) |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-12-04 11:18:08 (GMT) |
| commit | 961ec6daa7b14f376c30d447a830fa4783a2112c (patch) | |
| tree | fd4952bd65fa9e991de7687eaef4b2e5af7a0e70 /arch/arm/kernel/perf_event.c | |
| parent | 4d6b7a779be34e1df296abc1dc555134a8cf34af (diff) | |
| download | linux-fsl-qoriq-961ec6daa7b14f376c30d447a830fa4783a2112c.tar.xz | |
ARM: 6521/1: perf: use raw_spinlock_t for pmu_lock
For kernels built with PREEMPT_RT, critical sections protected
by standard spinlocks are preemptible. This is not acceptable
on perf as (a) we may be scheduled onto a different CPU whilst
reading/writing banked PMU registers and (b) the latency when
reading the PMU registers becomes unpredictable.
This patch upgrades the pmu_lock spinlock to a raw_spinlock
instead.
Reported-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/perf_event.c')
| -rw-r--r-- | arch/arm/kernel/perf_event.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 50c197b..624e2a5 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -32,7 +32,7 @@ static struct platform_device *pmu_device; * Hardware lock to serialize accesses to PMU registers. Needed for the * read/modify/write sequences. */ -static DEFINE_SPINLOCK(pmu_lock); +static DEFINE_RAW_SPINLOCK(pmu_lock); /* * ARMv6 supports a maximum of 3 events, starting from index 1. If we add |